Influence of waterlogging and lime or organic matter additions on the distribution of trace metals in an acid soil

Summary

A study has been made of the influence of waterlogging on the distribution of trace metals between the various reservoirs in which they are held in a soil. Selective extractants have been used to remove metals held in 4 ways: soil solution and exchangeable; specifically adsorbed by inorganic sites; adsorbed or chelated by organic sites; adsorbed onto oxide surfaces.

Waterlogging over a period of 16 weeks resulted in the release of both manganese and iron from the organic — and oxide — bound reservoirs to the soluble, exchangeable and inorganic reservoirs. Addition of both 1% dried grass (as an actively decomposing organic material) and 1% CaCO3 to the soil resulted in an acceleration of the metal redistribution.

For manganese, selective extraction methods accounted for the distribution of all the metal in the reservoirs studied. In the case of iron however, there appeared to be some release from a reservoir not being extracted.